How to Map a Hard Drive to a Directory

In my last post I mentioned that I have been exploring the option of backing up my data online. In that post I mentioned two services, Carbonite and Mozy. Although both were similar, Mozy was the only service that could backup data located on an external hard drive.

During my test with Carbonite, I managed to find a method of backing up my data from an external hard drive. This method involved mounting my external hard drive as a directory on my C drive. I will explain how I did that in this post.

Drive Letters and Paths

When you connect an external hard drive to your computer, Windows will assign it one of the unused drive letters on your computer. Unless you change drive letters of your devices regularily, Windows will continue to assign that drive letter to that hard drive.

If you choose to, you can assign another drive letter to that hard drive, or even a folder on another drive. In the case of Carbonite I assigned the drive to a folder, while still keeping the original drive letter. To assign a drive to a folder, use the following steps:

  1. Create a new directory on your computer. For this example, I created a directory called Backup on my C drive (C:\Backup).
  2. Right-click the My Computer icon on your desktop and select Manage from the popup menu.
  3. On the left, below Storage click Disk Management. A list of all the drives connected to your computer should be displayed on the right.
  4. Right-click the drive you want to map to the directory created in the first step and then select Change Drive Letter and Paths. A dialog box should open.
  5. Click the Add button.
  6. Select the Mount in the following empty NTFS folder option, and then enter the path to the folder, in my case I would enter C:\Backup. Alternatively you can click the Browse button and navigate to the folder.
  7. Click the OK button to save and close the window.
  8. Click the OK button on the next window to close that window as well.
  9. Open windows explorer and check the directory you have created. The contents of the directory should now be the same as the hard drive.

I found that this method worked with Carbonite to allow me to backup my data that was located on an external hard drive. It is important to note that you won’t be able to access the directory if the external hard drive is not powered on. Also, the drive letter that was assigned to the external hard drive will still be assigned to the hard drive. You will now have a directory and drive assigned to that hard drive.


While testing two online backup services (Carbonite and Mozy) I noticed that Carbonite didn’t allow data on an external hard drive to be backed up. I then mapped the external hard drive to a directory on my C drive and Carbonite was able to backup the files.

4 Responses to “How to Map a Hard Drive to a Directory”

  1. John says:

    Carbonite must have caught on to this and now discriminates external drives mounted as folders on internal drives. I guess their concern is whole networks will be backed up to a single Carbonite account.

    • Paul says:

      Not being able to back up from an external hard drive is what I didn’t like about Carbonite. All of my data is backed up to an external hard drive, and I don’t usually keep anything on the local drive. More people today are using external hard drives for backup, so I think Carbonite should a least support those.

  2. Kyle says:

    Wondering if this still works with Carbonite? Or have they closed this loop-hole?

    • Paul says:

      I wouldn’t exactly call this a loop-hole as at the time it was the only way to backup data from an external hard drive with Carbonite. I have since chosen Mozy for my online backup, so I’m not sure if Carbonite now allows you to backup directly from an external hard drive. If it doesn’t, then it should be fixed. Many people, myself included, have their data on an external hard drive instead of on the system drive. This allows me to keep my data safe in case I ever need to format my computer.

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